Here’s how Jason Day is able to hit a 2-iron almost 300 yards

Getty ImagesPONTE VEDRA BEACH, FL - MAY 12: Jason Day of Australia reacts on the 15th green during the first round of THE PLAYERS Championship at the TPC Stadium course on May 12, 2016 in Ponte Vedra Beach, Florida. (Photo by Mike Ehrmann/Getty Images)

Stop me if you’ve heard this one: Tour players hit the ball really far. No, seriously, really far. Even when they aren’t hitting it as far as they can. Consider Jason Day’s final hole of his blistering opening-round 63 at the Players.

Day stepped up to the tee at the 583-yard ninth hole and launched a 290-yard missile (some reports had at 297, some at 288). Not that impressive until you realize he hit it that far not with a driver or a fairway wood, but with an iron. That’s presumably because the other clubs would have gone too far, bringing into play the hazard that cuts across the fairway at about 325 yards.

Of course, he also admitted before the tournament that he and his 3-wood were having issues.

“There's a few 3-woods out there for me that I have to hit, and if there's one club in the bag that's uncomfortable for me at times, it's the 3-woods," he said. "That's why I might be hitting a few more 2-irons off the tee this week, just to try and get it in play."

Like many iron designs today, Day’s 2-iron, the TaylorMade RSi 2 (tour version), features nearly the level of spring-like effect for center hits that you would see on a driver. (The USGA limits spring-like effect on all clubs.) That’s because engineers at every golf company have figured out ways to thin the face and use more exotic materials to create more ball velocity. Those include special high-strength steels, slots, cupface constructions and variably thick geometries that make the face more flexible.

Specifically in this instance, TaylorMade uses slots in both the sole and the iron’s face to create more unsupported regions that allow the face to give at impact. Of course, it’s not as simple as cutting slots in a regular iron. The size and stiffness of the region around the slots has to be optimized so the face gives in the proper sequence with the ball’s deformation. Get the timing wrong between how the face flexes and how the ball deforms at impact and you don’t get maximum energy transfer.

That flexibility does three very important things for distance: It creates more ballspeed, it helps shots launch a fraction higher and it makes the ball come off the face with less spin. More speed, higher launch and less spin always means more distance. That technology matters for average players, too. Our own testing of average golfers showed that even today’s middle irons are juiced. A 5-iron of a decade ago flies lower and shorter than a modern 6-iron.

Day’s longest hits with his driver can reach well past 350 yards, so it’s not like the high spring-like effect on his 2-iron makes it perform exactly like a driver. Day’s driver is about five inches longer than his 2-iron (39.75 inches), and at 17 degrees, it has about 6.5 degrees less loft. The increased loft means impact isn’t as direct so the ball will lose a little speed compared to a driver and the five inches less shaft length (and a much heavier steel shaft vs. the 70-gram graphite shaft in his driver) also means less clubhead speed. Probably more like 105 miles per hour compared to Day’s occasional 123 miles per hour with the driver. Eighteen miles per hour less speed, even with a spring-like effect near the limit, is approximately 50 yards less distance (generally every 1 mile per hour of clubhead speed equates to three yards of distance).

Of course, 350-50 is 300, or just about what Day hit his hot 2-iron on Thursday.

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